Description

Farmer Ron in Colorado is building a ski resort for his cows (though budget constraints dictate construction of just one ski lift). The lift will be constructed as a monorail and will connect a concrete support at the starting location to the support at the ending location via some number of intermediate supports, each of height 0 above its land. A straight-line segment of steel connects every pair of adjacent supports. For obvious reasons, each section of straight steel must lie above the ground at all points. Always frugal, FR wants to minimize the number of supports that he must build. He has surveyed the N (2 <= N <= 5,000) equal-sized plots of land the lift will traverse and recorded the integral height H (0 <= H <= 1,000,000,000) of each plot. Safety regulations require FR to build adjacent supports no more than K (1 <= K <= N - 1) units apart. The steel between each pair of supports is rigid and forms a straight line from one support to the next. Help FR compute the smallest number of supports required such that: each segment of steel lies entirely above (or just tangent to) each piece of ground, no two consecutive supports are more than K units apart horizontally, and a support resides both on the first plot of land and on the last plot of land.

科罗拉州的罗恩打算为他的奶牛们建造一个滑雪场,虽然需要的设施仅仅是一部缆车.建造一部缆车,需要从山脚到山顶立若干根柱子,并用钢丝连结它们.你可以认为相对于地面,柱子的高度可以忽略不计.每相邻两根柱子间都有钢丝直接相连.显然,所有钢丝的任何一段都不能在地面之下.    为了节省建造的费用,罗恩希望在工程中修建尽可能少的柱子.他在准备修建缆车的山坡上迭定了N(2≤N≤5000)个两两之间水平距离相等的点,并且测量了每个点的高度H(O≤日≤10^9).并且,按照国家安全标准,相邻两根柱子间的距离不能超过K(1≤K≤N-1)个单位长度.柱子间的钢丝都是笔直的. 罗恩希望你帮他计算一下,在满足下列条件的情况下,他至少要修建多少根柱子:首先,所有的柱子都必须修建在他所选定的点上,且每一段钢丝都必须高于地面或者正好跟地面相切.相邻两根柱子的距离不大于K个单位长度.当然,在第一个点与最后一个点上一定都要修建柱子.

Input

* Line 1: Two space-separate integers, N and K

* Lines 2..N+1: Line i+1 contains a single integer that is the height of plot i.

第1行:两个整数N和K,用空格隔开.

第2到N+1行:每行包括一个正整数,第i+l行的数描述了第i个点的高度.

Output

* Line 1: A single integer equal to the fewest number of lift towers FR needs to build subject to the above constraints

输出一个整数,即罗恩最少需要修建的柱子的数目.

Sample Input 1

13 4
0
1
0
2
4
6
8
6
8
8
9
11
12

Sample Output 1

5

Source

BZOJ-1721

dp[i]表示前i个至少需要修建几根柱子。

图中情况肯定选红色的。所以倒着维护斜率就可以了。

dp[i]=max(dp[i] , dp[j] + 1)  ,  max(1,i-k) <= j <i && 斜率tmpk<=mink

 #include<bits/stdc++.h>
using namespace std; double a[];
int dp[];
const int inf=0x3f3f3f3f;
double work(int x1,int x2,double y1,double y2) {
return (y1-y2)/(x1-x2);
} int main() {
int n,k;
while(~scanf("%d%d",&n,&k)) {
for(int i=;i<=n;i++) {
scanf("%lf",&a[i]);
dp[i]=inf;
}
dp[]=;
for(int i=;i<=n;i++) {
double mink=1e100;
for(int j=i-;j>=max(i-k,);j--) {
double tmpk=work(i,j,a[i],a[j]);
if(tmpk<=mink) {
dp[i]=min(dp[i],dp[j]+);
mink=tmpk;
}
}
}
printf("%d\n",dp[n]);
}
}

BZOJ1721 Ski Lift 缆车支柱的更多相关文章

  1. [BZOJ1721][Usaco2006 Mar]Ski Lift 缆车支柱

    Description Farmer Ron in Colorado is building a ski resort for his cows (though budget constraints ...

  2. luogu 4909 [Usaco2006 Mar]Ski Lift 缆车支柱 动态规划

    可以出模拟赛T1? #include <bits/stdc++.h> #define N 5002 #define inf 1000000 #define setIO(s) freopen ...

  3. BZOJ-1721|线性dp-缆车支柱

    Ski Lift 缆车支柱 Description Farmer Ron in Colorado is building a ski resort for his cows (though budge ...

  4. bzoj AC倒序

    Search GO 说明:输入题号直接进入相应题目,如需搜索含数字的题目,请在关键词前加单引号 Problem ID Title Source AC Submit Y 1000 A+B Problem ...

  5. POJ2375 Cow Ski Area (强连通)(缩点)

                                        Cow Ski Area Time Limit: 1000MS   Memory Limit: 65536K Total Sub ...

  6. D - Cow Ski Area

    Description Farmer John's cousin, Farmer Ron, who lives in the mountains of Colorado, has recently t ...

  7. POJ 2375 Cow Ski Area

    Cow Ski Area Time Limit: 1000ms Memory Limit: 65536KB This problem will be judged on PKU. Original I ...

  8. Soj题目分类

    -----------------------------最优化问题------------------------------------- ----------------------常规动态规划 ...

  9. 【USACO2006 Mar】滑雪缆车 skilift

    [USACO2006 Mar] 滑雪缆车 skilift Time Limit 1000 msMemory Limit 131072 KBytes Description 科罗拉多州的罗恩打算为奶牛建 ...

随机推荐

  1. CS API 测试3

      //添加二级存储 http://192.168.150.16:8080/client/api? command=addSecondaryStorage& zoneId=7e34afc4-6 ...

  2. SqlServer——字符串处理函数

    1) ASCII Format:ASCII ( character_expression ) Function:返回表达式最左端字符的ASCII值. eg: select ASCII('abcdef' ...

  3. python学习——查找计算机中文件位置

    有时想查找某个文件时,却忘记了文件在计算机中存放的位置,这是一个经常遇到的问题. 当然如果你使用windows 7的话,可以直接用右上角的搜索框来搜索. 最近在学习python,正好拿这个来练练手,写 ...

  4. code3027 线段覆盖2

    dp 数据:d[i].a d[i].b d[i].v 分别表示第i条线段的起始点,结束点,价值 先按d[i].b排好序 dp[i]表示前i条线段的最大价值 方程: dp[i]=max{ dp[i-1] ...

  5. linux进入单用户方法-乾颐堂

    RedHat7.2 在使用GRUB引导程序的时候如何进入单用户 1.在出现GURB引导画面时,按字母e,进入GRUB编辑状态 2在引导菜单后添加“1”或single,选定它,然后按字母b,就可引导到单 ...

  6. ubuntu 16.04 Samba服务器搭建

    搭建Samba服务器是为了实现Linux共享目录之后,在Windows可以直接访问该共享目录. 现在介绍如何在ubuntu 16.04系统中搭建Samba服务. 1.安装Samba服务 sudo ap ...

  7. linux 下 使用wget 下载 jdk资源 命令

    wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-co ...

  8. console对象的理解

    console对象代表浏览器的JS控制台,虽然不是标准,但已经成为事实的标准 console对象的作用 a.显示代码运行错误信息 b.提供一个命令行接口,用来与网页互动 console对象拥有很多方法 ...

  9. springdata -----操作ES

    一:配置springdata-Es elasticseach-JPA.xml <?xml version="1.0" encoding="UTF-8"?& ...

  10. SQL2000中创建作业(定时查询,更新)(转)

    出处:http://blog.csdn.net/xys_777/article/details/5683413 SQL2000中创建作业(定时查询,更新)企业管理器 --管理 --SQL Server ...